Club for Growth spokesman Rachael Slobodien insisted that the ad was still airing. At least one listener said he heard the ad Friday evening on WORD 106.3 FM.

The ad, featuring the voices of two men with thick Southern accents, refers to Timmons and Hamilton as "Trump-trashers."

Timmons' campaign sent out a cease-and-desist letter calling for the ad to be shelved.

At a news conference Friday in Greenvlle, Timmons said the ad "mischaracterized" an Oct. 25 Facebook comment that he made about a post by U.S. Rep. Jeff Duncan.

"I absolutely have major issues with many things Trump does and says," Timmons wrote in the Facebook comment. He added, however, "Overall, the policies being pursued by the White House are helping salvage what otherwise could have been the end of our country."

Speaking at the news conference, Timmons said, “I support the president. I mean I don’t support grabbing women inappropriately and I don’t support banning all auto imports from Germany, but I support the president’s policies. I support his effort to make America great again. I think we are on the right track, and I think that he just needs more people in Washington and that are willing to fight alongside him to help get our country back on track.”

In a statement, national Club for Growth President David McIntosh said, "Mr. Timmons confirms he said that nasty thing about Trump, but he whines that he said other things, too.”

"So, like a typical politician, Mr. Timmons wants to get away with speaking out of both sides of his mouth," McIntosh said.

Hamilton issued a statement Friday saying that he received an A grade from the South Carolina Club for Growth.

He and Timmons pointed out that national Club for Growth paid for ads opposing Trump before he won the Republican presidential nomination in 2016.

“Their ad is just insulting. The people talking in the ad sound like a bunch of hillbillies," he said. "Is this what these elitists in Washington think of the Upstate?”

Timmons said that he believes the ad was meant to aid Josh Kimbrell, the former host of an Upstate radio show who also is running for South Carolina's 4th Congressional District seat.

“The Club for Growth has found their swamp creature — the person that they can control. That’s Josh Kimbrell," Timmons said. "He is a convenient conservative. He led the never-Trump train on his radio show and on Facebook, and there is evidence of that is all over the place."

At the end of the news conference, Timmons distributed copies of comments that Kimbrell made about Trump on Facebook in 2015.

"Yes, I did say that I couldn't vote for Donald Trump on the show tonight," stated Kimbrell in an Oct. 20, 2015, post on Facebook. "Can't stand him, and he's not conservative. I'll stand by comment."

Timmons also said Kimbrell "led the effort for a massive sales tax increase in Spartanburg."

"Conservatives do not raise taxes," Timmons said. "We cannot send someone to Washington that is beholding to the special interests before he even gets there.”

Kimbrell responded to Timmons' comments later Friday. He said his campaign had nothing to do with the ad about Timmons and Hamilton.

"I voted for Donald Trump," he said. "I have also been on the radio every day since he won the nomination supporting the president's election and then defending and advancing his policies."

As chairman of the Spartanburg County Republican Party, Kimbrell said, he supported holding a 2017 sales tax referendum instead of having county officials increase property taxes. Voters in that county approved the sales tax increase.

Kimbrell questioned Timmons' conservative principles, citing his efforts to pass legislation that allowed Greenville Health System to change from a public nonprofit organization to a private nonprofit.

Timmons and Kimbrell have gathered the largest campaign war chests among the 12 Republicans running for the congressional seat that represents most of Greenville County and all of Spartanburg County.

Recently filed reports show that Timmons had collected about $1 million, including $885,000 in loans, compared to nearly $307,000 for Kimbrell.

As the June 12 primary approaches, private polls have consistently shown that former state Sen. Lee Bright of Spartanburg County is the front-runner in the race. Several candidates — including Timmons, Hamilton and Kimbrell — are hoping to finish in the top two and advance to a likely June 26 runoff.

Follow Kirk Brown on Twitter @KirkBrown_AIM and email him at kirk.brown@independentmail.com